newbie question


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting newbie question
# 1  
Old 08-08-2006
newbie question

hey all, I have repeatedly seen scripts containing the following syntax,

grep "hello" $myfile >> $log 2>&1

can anyone explain exactly what "2>&1" mean? THANK YOU
# 2  
Old 08-08-2006
Care to read the man pages ? See the section REDIRECTION under man sh.
# 3  
Old 08-08-2006
while i am waiting other to help on my question, let me explain it to you !!

grep "hello" $myfile >> $log -----> all standard output will go into $log, except error which will output to your screen.

for this reason,we use 2>&1 ----> so that (2)=all error will go into (1)=standard output which you have already define as $log

so all output including error message wll all go into $log

Anyway man page will explain in more detail....
# 4  
Old 08-08-2006
If you find man page not very interesting.These two links will give you idea about file descriptors (2>...>&1)

link 1

link 2
# 5  
Old 08-08-2006
In unix 1 is defaut file descriptor for stdout and 2 is default file descriptor for stderr. So when you try redirecting on any of them you will redirect the stderr or stdout to a file or /dev/null.

regards
Apoorva Kumar
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

newbie question

Hi all, I am sure this is very simple but I cant quite get it. I am trying to search textfile1.txt for a string then take the results of the search and append the result to textfile3.txt So far I have used $ find file1.txt -exec grep "string i am looking for" '{}' \; -print this... (2 Replies)
Discussion started by: radgator
2 Replies

2. Shell Programming and Scripting

perl newbie . &&..programming newbie (question 2)

Hello everyone, I am having to do a lot of perl scripting these days and I am learning a lot. I have this problem I want to move files from a folder and all its sub folders to one parent folder, they are all .gz files.. there is folder1\folder2\*.gz and there are about 50 folders... (1 Reply)
Discussion started by: xytiz
1 Replies

3. UNIX for Dummies Questions & Answers

UNIX newbie NEWBIE question!

Hello everyone, Just started UNIX today! In our school we use solaris. I just want to know how do I setup Solaris 10 not the GUI one, the one where you have to type the commands like ECHO, ls, pwd, etc... I have windows xp and I also have vmware. I hope I am not missing anything! :p (4 Replies)
Discussion started by: Hanamachi
4 Replies

4. Programming

Newbie question

Dear all, I have a question related to parallel programing and if you can give me some hints on how to deal with it, it would be really great. I would like to run a small application on a supercompter of 128 CPUs. Unfortunately, on this machine only jobs which require 32 CPUs are allowed to... (1 Reply)
Discussion started by: Eduard
1 Replies

5. UNIX for Dummies Questions & Answers

Newbie question?

What is the best way to learn UNIX on the web, with out buying books? any link would be much help. Thank you in advance, L (1 Reply)
Discussion started by: lsoria1
1 Replies

6. UNIX for Dummies Questions & Answers

newbie question

I am taking a db classes toward oracle 10g. I am taking unix as well . I need to know what is the best option for os . should I use linux fedora. or get a sun box and start learning from there. Thanks (6 Replies)
Discussion started by: xzyan
6 Replies

7. UNIX for Dummies Questions & Answers

Very new newbie question

sorry if im not asking inthe right spot but, how do you turn the beeping off every time you hit a key onthe keyboard. I tried the click -n but it told me it didnt recognize click any help would be greatly appreciated ( the beeping is not going over well in the surrounding cubicles) thank you... (4 Replies)
Discussion started by: Split100
4 Replies

8. Shell Programming and Scripting

Newbie question

Hello, I have text file while looks this test1 test2 test3 test4 test5 test6 and if I want to parse it and make new file which would like this test1 test2 test3 test4 test5 test6 How can I do this in korn shell script Thanks (9 Replies)
Discussion started by: peeyush_23
9 Replies

9. UNIX for Dummies Questions & Answers

Newbie Question

Hi, I have a file, that is delimited by :: and the purpose of this file is none of your business. ;) There are about 65000 lines in this file, and there are lines that I would like to remove. About 45000 of them. Is there some sort of commands that I can run, to remove word(s) from this... (4 Replies)
Discussion started by: th3gh05t
4 Replies

10. UNIX for Dummies Questions & Answers

newbie question

hi im thinking of getting unix but i have no idea where to start I know that its an OS similar to linux but what hardware does in run on? i've heard of solaris but im not quit sure what it is thankxs (3 Replies)
Discussion started by: ninja
3 Replies
Login or Register to Ask a Question